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CVE-2017-1000255

Published: 09 October 2017

On Linux running on PowerPC hardware (Power8 or later) a user process can craft a signal frame and then do a sigreturn so that the kernel will take an exception (interrupt), and use the r1 value *from the signal frame* as the kernel stack pointer. As part of the exception entry the content of the signal frame is written to the kernel stack, allowing an attacker to overwrite arbitrary locations with arbitrary values. The exception handling does produce an oops, and a panic if panic_on_oops=1, but only after kernel memory has been over written. This flaw was introduced in commit: "5d176f751ee3 (powerpc: tm: Enable transactional memory (TM) lazily for userspace)" which was merged upstream into v4.9-rc1. Please note that kernels built with CONFIG_PPC_TRANSACTIONAL_MEM=n are not vulnerable.

From the Ubuntu security team

It was discovered that on the PowerPC architecture, the kernel did not properly sanitize the signal stack when handling sigreturn(). A local attacker could use this to cause a denial of service (system crash) or possibly execute arbitrary code.

Priority

High

CVSS 3 base score: 5.5

Status

Package Release Status
linux
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
Patches:
Introduced by 5d176f751ee3c6eededd984ad409bff201f436a7
Fixed by 265e60a170d0a0ecfc2d20490134ed2c48dd45ab
Introduced by 5d176f751ee3c6eededd984ad409bff201f436a7
Fixed by 044215d145a7a8a60ffa8fdc859d110a795fa6ea
linux-armadaxp
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
This package is not directly supported by the Ubuntu Security Team
linux-aws
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-azure
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-euclid
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-flo
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-gcp
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-gke
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-goldfish
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-grouper
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-hwe
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-hwe-edge
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-kvm
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-linaro-omap
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-linaro-shared
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-linaro-vexpress
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-quantal
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
This package is not directly supported by the Ubuntu Security Team
linux-lts-raring
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-saucy
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
This package is not directly supported by the Ubuntu Security Team
linux-lts-trusty
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-utopic
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-vivid
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-wily
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-lts-xenial
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-maguro
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-mako
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-manta
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-oem
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-qcm-msm
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-raspi2
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-snapdragon
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)
linux-ti-omap4
Launchpad, Ubuntu, Debian
Upstream
Released (4.14~rc5)